Final week sections

We will finish chapter 3 on Wednesday afternoon-- the trace-determinant plane, and 3-dim systems.

Then we will be doing a quick coverage of three important topics:
1. Forcing and resonance (Read 4.1 - 4.3) Th
2. Nonlinear dynamics (Read 5.1 and 5.2)  Fr
3. Laplace Transforms (Read 6.1 - 6.3) M

Recall that the final Monday afternoon and all day Tuesday will be entirely application of differential equations presentations.